Waterproof fabric and process for producing the same



A; B. HARRISON. WATERPROOF FABRIC AND PROCESS FOR PRODUCING THE SAME.

APPLICATION FILED MAY 17. 1915.

Patented July 20, 1920.

ATTORNEYS PATENT. OFFICE.

ARTHUR B. HARRISON, OF NEW YORK, N. Y.

WATERPROOF FABRIC AND PROCESS FOR PRODUCING THE SAME.

mamas.

Specification of Letters Patent.

Patented July 20, 1920.

Application filed May 17, 1915. Serial No. 28,536.

This invention relates to a novel fabric coated and saturated orimpregnated .with a bituminous substance and particularly with asphalticbitumen, and to a process for producing such a fabric; and it comprises,as a new article of manufacture, a fabric made waterproof, andparticularly woven cotton fabric, coating and impregnating it with asuitable bituminous substance substantially free from solvents, oils andfluxes, said fabric being flexible without cracking at ordinarytemperatures; more specifically it 5 comprises such a fabric coated andimpregnated with relatively 'pure asphaltic bitumen of a melting pointof about 175 to 200 F. forced into the fabric under pressure 1 when in amolten condition; it further com- 0 prises an elastic woven fabric suchas drill which is elastic in' all-directions, and which is coated andimpregnated with such bitumen or bituminous substance; and, as aprocess, it comprises a process of coating and impregnating such fabricwith such bituminous substance by immersing the fabric in a molten massof such substance, passing .the fabric while im- .mersed between aseries of sets of steam 40 heated rolls for compressing the fabric andforcing the bituminous substance therein, passing the fabric after suchtreatment over a heated drum andsubjecting it to'further compressionbetween rolls and such drum,

finishing and smoothing the fabric by means of heated finishing rolls,and cooling the res'ulting fabric; and it also comprises certain novelmodifications of the product, and certain specific features andsub-combinations of the process; all as more fully hereinafter set forthand as claimed.

In waterproofing fabrics foruse in tunnels, foundations, and othersub-level structures, bridge and deck floors, etc., particularly Wherethe fabric is subjected to acids or alkalis, such as occur in cementstructures or cinders, etc., it is important that the fabric bethoroughly saturated and impregnated as well as coated with thewaterproof- 1ng agent. It is also important in many cases, for thefabric to be more or less elastic n order that it may readilyaccommodate ltself to unevennesses of the surface to wh1ch applied.Close fiber fabrics suchas tar paper or felt have little if anyelasticity, and it is difficult to obtain more than a surface coating ofsuch materials with bituminous material. It has heretofore been proposedto dissolve such bituminous substances m a solvent, or compound themwith still bottoms, petroleum residues, volatile oils, or similarbitumen solvents, mixed or.

used as a flux, in order to make a more llquid mixture or solution forimpregnatmg such fabrics; but in such cases the tendency is for the morepenetrating solvent or flux to saturate the close fiber fabric and forthe bitumen to be deposited only on the outside, the felt or paperacting as a filter for the bitumen. As a result, the fluxes and solventstend to be retained in the fabric, and when the fabric'is used, as insub-level conditions of waterproofing, the bitumen tends to soften andbe disintegrated. The novel fabric of the present invention overcomessuch disadvantages, and possesses besides particularly valuableproperties which adapt it for general waterproofing uses, including useswhere it is subjected to acids or alkalis or to the other disintegratingelements of sub-level construction.

' The fabric which I use in making my new waterproof membrane is cottonfabric. Cotton itself, consisting of nearly pure cellulose, is notreadily attacked by acids or alkalis, and accordingly is much moreresistant than many other fibers, such as, for example, burlap,whichconsists of hemp, a ligno-cellulose, and when treated according tothe process of the present invention, it

becomes particularly resistant against attack. A particularly valuableform of cot ton fabric for use in making my novel waterproof fabric isthat known as drill, a peculiar weave which is elastic in alldirections, and which has a stretch of e. 9., 10 to 13% in alldirections, without breaking. When waterproofed according to the presentinvention, it still retains its. valuable elastic properties, being thuscapable of use on uneven surfaces where fabric of a straight Weave,capable of being stretched only on the bias, is less suitable.Accordingly, while I refer to cotton fabrics generally as ineludedwithin the invention, when treated as hereinafter described, I considerthe waterproof membrane made of such elastic fabric as a particularlyvaluable and advantageous embodiment of the invention.

- The cotton fabric is treated and thoroughly saturated and impregnatedwith pure bitumen or a bituminous substance so that every fiber isthoroughly treated and rendered resistant and impervious to the actionofelements met with in belowgrade or sub-level work, and therefore isprevented from rotting or.- decay by such elements. The bitumen orbituminous substance which I may use in impregnating such fabric may beeither coal-tar (freed from its more volatile constituents) or asphalt,or combina-- tions of both, or other suitable bituminous substance, freefrom flux or solvent. A form of bitumen which I have found after longand careful study and experiment, to be particularly advantageous, isasphaltic bitumen melting at approximately 190 F., or varying in meltingpoint from about 175 F. to 200 F. Much higher temperatures are, however,necessary to make such a bitumen thinly fluid, e. g. around iOO F., but

since cotton tends to char or carbonize ataround 250 F such highertemperatures are precluded. Bitumens of lower melting point which arethinly fluid at lower temperatures, Whether of coal tar or asphalticnature, often become sticky in hot weather tosuch an extent as to maketheir use impracticable, rolls of fabric impregnated with such lowermelting-bitumens often becoming so stuck together as to preventunrolling. In using the higher melting bitumens which cannot be used attemperatures which make them thinly fluid, the thorough impregnation ofthe fabric in order to obtain a uniform coating and impregnation of allthe fibers, presents peculiar difficulties. Nevertheless, I effect suchimpregnation by the process and apparatus of the present invention in aparticularly advantageous manner. In this process the bituminoussubstance is melted or liquefied and kept at a temperature not exceedingabout 250 F. The fabric is immersed in this molten mass and whileimmersed is subjected to pressure successively by a series of rollsarranged in pairs, the fabric passing through the molten mass betweenthe different sets of rolls, so that it is alternately immersed andsqueezed or compressed. The fabric is then further compressed betweenheated -rolls after immersion, and is finally given asmoothing orfinishingtreatment and cooled I before winding into rolls.

The accompanying drawing illustrates, more or less diagrammatically, andwith parts in section, an apparatus appropriate to the production of thenovel product of the present invention. This apparatus is made up of avessel or receptacle 1 mounted, on supports 2 and arranged to be heatedby the heating rolls therein, or by other suitable regulable heatingmeans such as a steam jacket (not shown). Within the receptacle are fivepairs of steam heated rolls 3, 4, spaced apart, between which the fabricis passed from the roll of raw cloth 6 and the idler 5. The steam heateddrum 7 is arranged to be partly submerged in the molten mass within theapparatus, and rolls 8, 9 and 10 are arranged to press against thisdrum. Smoothing rolls 11 and 12, one above and the other below thefabric, are arranged to act thereon after the fabric leaves the roll10,-and a cooling conduit 13 of a width sufficient to accommodate thefabric and of a suitable depth, 0. g. eight inches, is connected with ablower 14 arranged to discharge a blast of cold air against the fabricduring its passage to the roll 15. The feeding of the fabric and theoperation of the rolls, to vary their pressure and the tension of thefabric, can be regulated by any suitable means, not shown.

In carrying out the process of the present invention in the apparatusabove described, the bitumen will be maintained in a molten condition bymeans of the steam heated rolls immersed therein or by means of otherheating means (not shown), the temperature of the molten mass beingmaintained below that ofdecomposition of the fabric being treated. Thefabric is unrolled from the roll 6 and passes up over the idler 5 andinto the molten mass. There it passes successively between the five setsof steam contact with the molten bitumen between each passage throughthe rolls. Thus the bitumen upon the fabric is compressed in the fabricby each pair of rolls and the fabric is given five successivecompressions following contact or immersion in the molten bitumen. Thefabric then asses up over the steam heated drum 7 w ere'it issuccessively compressed by the rolls 8, 9 and 10. The steam drum ispartly submerged in the molten mass and carries a layer of the bitumenup with it into contact withthe fabric. The action of these rollspressing against the steam drum is to further compress and contact thebitumen within the fabric so that the desired coating and impregnationis insured. The fabric then passes between the two finishing tubes 11and 12 heated to a temperature of 'e. g. 200 F., by steam, one tubescraping the cloth on the upper side and one on the lower side. Thesetubes act as smoothing or finishing ne ates such treatment is flexibleat all ordinary temperatures so that it can be folded back upon itselfany number of times without cracking or fracture, and it will remain inthe roll at high temperatures, even up to about 150 F., without stickingor bonding together, so that it can be easily unrolled when desired.When the fabric used is of an elastic nature, such as drill, the treatedand waterproofed fabric will still be elastic and will have a stretch ofabout 10% in any direction without breaking. Accordingly the fabric canreadily conform to any unevennesses in the surface to which it isapplied without leaving pockets bridges or air I holes. The cottonfabric, moreover, is much coated and impregnated with an inertbitustronger than many of the closer fiber fabrics, such as felt andpaper. For general waterproof purposes the cotton fabric should be ableto withstand a weight of at least 125 pounds per inch without breakage.The novel fabric of the present invention, made up of cotton which isitself chemically inert to acids and alkalis, such as are usually metwith in sub-surface waterproofing, is by the present inventionthoroughly men, advantageously of asphaltic origin, which is compressedwithin the fabric and which is free from fluxes and solvents. Such abitumen is tough and inert and when containing, for example, 98%hydro-carbon, is not aflected by concentrated acids and alkalis. Thefabric moreover contains no oils which might cause disintegration orrotting of the fiber, or softening of the bitumen when used. Such afiber when saturated with a bitumen of sufliciently high melting pointis efficient under all weather and climatic conditions. It isadapted foruse as a membrane for water-proofing foundations of buildings or ofother structures, in tunnels, on the floors of bridges or decks, or ingeneral wherever a waterproof fabric is desired capable of withstandingdisintegrating conditions. The fabric may be made of dif ferent weaves,weights and thicknesses, in order to adapt it for different uses. Sincethe only material-used for impregnating is the pure bitumen, the fabriccan advantageously be used as a binder between differentlayers ofbitumen, the bond in such cases being between bitumen and, bitumen onboth sides. While I have described what I now believe to be the bestmethod of producing such a fabric, yet it will be understood that theinvention is not limited to the exact method and apparatus described,although such method and apparatus are particularly advantageous, but itwill be understood that variations and modifications can be made in thespecific embodiments of the invention described without departing fromits spirit and scope.

I claim:

1. As a new article of manufacture, a woven cotton fabric coated andimpregnated at a temperature below that injurious to the cotton fabricwith a hot fluid bitumen ductile at all ordinary temperatures andsubwoven cotton fabric coated and impregnated at a temperature belowthat injurious to the cotton fabric with a hot fluid asphaltic bitumenof a melting point of about 175 to 200 F. and substantially free frombitumen solvents and fluxes, said coated and impregnated fabric beingflexible at all ordinary temperatures.

4. As a new article of manufacture, an elastic woven cotton fabriccoated and impregnated at a temperature below that injurious to thecotton fabric with a hot fluid asphaltic bitumen of a melting point ofabout 17 5 to 200 F. and substantially free from bitumen solvents andfluxes, said coated and impregnated fabric being flexible at allordinary temperatures, and being elastic and capable of being stretchedabout 10% in all directions.

5. The method of coating and impregnating woven cotton fabric and ofproducing therefrom a fabric coated and saturated with a bituminoussubstance substantially free from bitumen solvents and fluxes, whichcomprises passing the fabric through a molten bituminous substancesubstantially free from bitumen solvents and fluxes at a temperaturebelow that injurious to the cotton fabric and subjecting the fabric tocompression between heated rolls during its immersion, whereby thebituminous sub stance is forced into the fabric mechanically without theaid of solvents and fluxes.

6. The method of coating andimpregnating woven cotton fabric and ofproducing therefrom a fabric coated and saturated with a bituminoussubstance substantially free from bitumen solvents and fluxes, whichcomprises passing the fabric through molten asphaltic bitumen heated toa tem perature below that injurious to the cotton fabric, said bitumenbeing substantially free from bitumen solvents and fluxes, andsubjecting the fabric to alternate compression between heated rolls andexposure to bitumen during its immersion, whereby the bituminoussubstance is forced into the fabric mechanically without the aid ofsolvents and fluxes.

7. The method of coating and impregnating woven cotton fabric and ofproducing therefrom a fabric coated and saturated I with a bituminoussubstance substantially free from bitumen solvents and fluxes, whichcomprises passing the fabric through a molten mass of asphaltic bitumenmelting at about 175 to 200 F. heated to a temperature below thatinjurious to the cotton fabric and subjecting the fabric while passingthrough the molten mass to repeated compression between heated rolls,the action of the rolls being sufficient to cause the desiredimpregnation or saturation of the fabric with the molten bitumen withoutthe use I of bitumen solvents and fluxes.

worked into the fabric mechanically while immersed, and whereby thefabric is further subjected to the mechanical impregnating action afterimmersion.

9. he process of coating and impregnating fabrics which comprisespassing the fabric through a molten mass of asphaltic bitumen melting atabout 175 to 200 F. maintained at a temperature below about 250 F. andsuccessively subjecting the fabric to compression between heated rollsand to contact with the bitumen, subjecting the fabric after immersionto further compression betweena drum heated to about 250 F., and aseries of coacting rolls, and cooling the fabric.

10. The process of coating and impregnating fabrics which comprisespassing the fabric through a molten mass of'asphaltic bitumen melting atabout 175 to 200 F.

250 F. and successively subjectingthe fabric to compression betweenheated rolls and to contact with the bitumen, subjecting the: fabricafter immersion to further compres sion between a. drum heated to about250. 5

F., and a series of coacting ro11s,'smoothing the fabric by passagebetween finishing rolls heated to about 200 F., and cooling t e fabric.

11. The process of coating and impregnating fabrics which comprisespassing the fabric through a molten mass of asphaltic bitumen melting atabout 175 to 200 F. maintained at a temperature below about 250 F. andsuccessively subjecting the fabricto compression between heated rollsand to contact with the bitumen, subjecting the fabric after immersionto further compression between a drum heated to about 250 F., and aseries of coacting rolls, smoothing the fabric by passage betweenfinishing rolls heated to about 200. F., and cooling the fabricbysubjecting the same to a blast and current of cold air.

In testimony whereof I affixm si ature.

- ARTHUR B. HAl R SON.

65 maintained at a temperature below about '1

